Monodevelop has unhandled exception when trying to add an XML schema

Binary package hint: monodevelop

I experienced an unhandled exception in Monodevelop when trying to add an XML schema.

dpkg -l monodevelop
||/ Name Version Description
+++-===================-===================-======================================================
ii monodevelop 2.4+dfsg-1ubuntu1 Development Environment for GNOME

To recreate, just select Edit > Preferences > XML Schemas > Add

You'll then see an unhandled exception with the text below:

System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.NullReferenceException: Object reference not set to an instance of an object
  at MonoDevelop.XmlEditor.XmlEditorService.BrowseForSchemaFile () [0x00000] in <filename unknown>:0
  at MonoDevelop.XmlEditor.Gui.XmlSchemasPanelWidget.addRegisteredSchema (System.Object sender, System.EventArgs args) [0x00000] in <filename unknown>:0
  at (wrapper managed-to-native) System.Reflection.MonoMethod:InternalInvoke (object,object[],System.Exception&)
  at System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) [0x00000] in <filename unknown>:0
  --- End of inner exception stack trace ---
  at System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) [0x00000] in <filename unknown>:0
  at System.Reflection.MethodBase.Invoke (System.Object obj, System.Object[] parameters) [0x00000] in <filename unknown>:0
  at System.Delegate.DynamicInvokeImpl (System.Object[] args) [0x00000] in <filename unknown>:0
  at System.MulticastDelegate.DynamicInvokeImpl (System.Object[] args) [0x00000] in <filename unknown>:0
  at System.Delegate.DynamicInvoke (System.Object[] args) [0x00000] in <filename unknown>:0
  at GLib.Signal.ClosureInvokedCB (System.Object o, GLib.ClosureInvokedArgs args) [0x00000] in <filename unknown>:0
  at GLib.SignalClosure.Invoke (GLib.ClosureInvokedArgs args) [0x00000] in <filename unknown>:0
  at GLib.SignalClosure.MarshalCallback (IntPtr raw_closure, IntPtr return_val, UInt32 n_param_vals, IntPtr param_values, IntPtr invocation_hint, IntPtr marshal_data) [0x00000] in <filename unknown>:0

I did not experience this error with Monodevelop 2.2. Thanks for your help!